You and your oncolog. You and your oncologist need to discuss this. Given the low stage, and assuming successful completion of treatment, pet/ct might not be indicated at this time. It does depend on the specifics of your case.
Pet/ct is useful in evaluating for distal metastatic disease. It does not replace mammography, ultrasound or breast MRI for local recurrence surveillance .

No. If all of your treatment is completed as you are followed by your oncology team with breast exams, mammograms and md breast exams, pet scan will offer little to no benefit. There r also some blood markets that can be used to evaluate for early recurrence and this merit additional studies. Routinely though after treatment for an early stage breast cancers do not require pet scan for surveillance.

Technically no. Technically no. But i would still consider getting one ( if you can afford one , or if your insurance will consent ) for piece of mind. Remember a pet/ct scan covers your head to thigh and could some other , non-symptomatic areas of concern.

PET . Pet scans are not proven to be of use in stage i breast cancer. There is a new type of breast-only pet canning called pem zthat is currently being tested, but right now there it also has no established role in monitoring you for recurrence or a new cancer. Glad to hear the mammo was clear and wish you the best. For now an annual mammo, possibly with an ultrasound, is the best testing after treatment for an early stage breast cancer. There are some woman with a particularly higher risk of recurrence or of developing a second new tumor who will also benefit from regular MRI scans. Ask your doctors if they think you need this too.